Adjustable latching mechanism



Feb. 19, 1957 N. M. cAsE ADJUSTABLE LATCHING MECHANISM Filed Sept. 9, 1955 In l enl5r Nor-75: M. Uase, y awn ni d S es P ten ADJUSTABLE LATCHING MECHANISM Norton M. Case, Lenox, Mass, assignor to General Electric Company, a corporation of New York Application September 9, 1955, Serial No. 533,474

6 Claims. (Cl. 200-116) This invention relates to an adjustable latching mechanism, and more particularly, to a mechanism for adjusting the trip point of a circuit interrupter or breaker.

In one prior art form of .circuit breaker, shown in Favre Patent 2,487,534, issued November 8, 1949, and assigned to the same assignee as the instant patent application, the circuit breaker is provided with an indicating means which is tripped to the indicating position prior to tripping open of the circuit breaker. Such sequence is desired to give a warning of the fact that the protected apparatus, such as a transformer, is overloaded sufficiently to affect the expected life of the transformer, and that if the degree of overload continues to rise the circuit breaker will be tripped open. in this type of circuit breaker means is provided to adjust the trip point of the circuit breaker. However, when the circuit breaker trip point is raised the indicating mechanism trip point is correspondingly raised. it would be desirable to adjust the .circuit breaker trip point without affecting the indicating mechanism trip point. For instance, in order to accommodate peak load periods rather than have the circuit breaker trip open one would raise the trip point of the circuit breaker. However, it would be preferable to do this without raising the trip point of the indicating mechanism so that one would always know when the transformer is overloaded sufficiently to affect its expected life.

Accordingly, it is an object of this invention to provide in a circuit breaker having an indicating means which is tripped to the indicating position prior to tripping open of the circuit breaker an adjusting mechanism for adjusting thetrip point of the circuit breaker without altering the trip point of the indicating means.

It is a further object of this invention to provide in a circuit breaker having an indicating means which is tripped to the indicating position prior to tripping open of the circuit breaker a low cost and uncomplicated adjustable latching mechanism for adjusting the trip point of the circuit breaker without altering the trip point of the indicating means, and which can be readily assembled into an existing form of such circuit breaker.

My invention comprises an adjustable latching mechanism having a movable latching element engaged by two releasable trip elements and releasable one after the other upon movement of said latching element, said latching element having two straight latching edges for engagement with said trip elements, said edges disposed with respect to each other at an angle, and said latching element movable in a direction parallel to the edge with which one of said trip elements is engaged.

In a circuit breaker having an indicating means trip element which is tripped prior to tripping of a trip element of said circuit breaker, my invention comprises means for adjusting the trip point of said circuit breaker trip element without altering the trip point of said indicating means trip element, said adjusting means comprising a movable latching element having two straight line edges therein disposed with respect to each other at an angle and releasably engaged by said trip elements, said latchice ing element mounted for movement in a direction parallel to the edge with which said indicating means trip element is engaged.

In a circuit interrupter having an indicating means which is tripped to the indicating position before said circuit interrupter is tripped open, my invention comprises adjusting means for adjusting the trip point of said circuit interrupter without altering the trip point of said indicating means, said adjusting means comprising a movable latching element having two straight latching edges disposed with respect to each other at an angle and releasably engaged by two tn'p elements, said latching element being mounted for movement in a direction parallel to one of said edges.

The features of my invention which I believe to be novel are set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawing.

In the drawing Fig. l is a partly broken away perspective view of one form of my invention. Fig. 2 is a partly broken away top view of the form of my invention illustrated in Fig. 1. Fig. 3 is a partly broken away top view of another form of my invention. Like reference numerals will be used throughout the various figures to indicate like elements.

Referring now particularly to Fig. 1, shown therein is a partly broken away perspective view of the circuit breaker of the heretofore mentioned Favre Patent 2,487,534. Only those circuit breaker parts are disclosed which are believed to be necessary for a clear understanding of my invention, and for other parts of the circuit breaker one may refer to said Favre patent. The circuit breaker comprises a pivotally mounted latching bar 1 which is capable of pivoting about its lengthwise axis. Bar 1 is pivotedrearwardly or in a clockwise direction when viewing Fig. 1 by a finger 2 which is movable upwardly in accordance with the degree of overloading of the protected apparatus or transformer, and bar 1 is spring biased forwardly or in a counterclockwise direction. Movably mounted on the upper surface of the bar 1 is a latching strip element or elongated plate 3 whose operation will be described more fully hereinafter.

Projecting above plate 3 is a U-shaped support 4.

stationary indicating or signal means contact 5 is insulatingly suspended from the upper bridge portion of support 4. A pair of vertically disposed guide slots 6 are formed in the opposite leg portions of the support 4 for the pur-.

pose of guiding a movable indicating or signal means rod-like contact 6'. The right-hand end of contact 6' when viewing Fig. 1 has a generally vertically disposed releasable indicating or signal means trip element 7 connected thereto as by welding. The upper end portion of trip element 7 i guided by a slot formed in a bracket 8 portion of the trip connected to support 4 and another element 7 abuts an adjusting screw 9 by virtue of a wardly and downwardly directed spring 10.

Positioned forwardly of the plate 3 is a releasable circuit interrupter or circuit breaker trip element 11. A

rear

rear portion of the trip element 11 has a latching tooth 12; formed therein, and as will be obvious to thosetskilled in the art and from said Favre patent, when the tooth 12 is released from the plate 3 the contacts of the circuit interrupter or breaker will be moved to the tripped open position. When the lower end portion of the jtrip ele-.

ment 7 is released from the plate 3 the movable contact- 6 will be tripped into engagement with the stationary contact 5 to close a signal light circuit or the like. The degree of overlap of the lower end portion of trip element 7 with respect to the plate 3 is less than that of 3 tooth 12 whereby when the bar 1 is pivoted rearwardly the indicating or signal means is tripped to an indicating condition before the circuit interrupter or breaker contacts are tripped open. The trip point of the trip element 7 can be adjusted independent of the trip point of the trip element 11 at the screw 9.

Referring now also to Fig. 2, the forward peripheral portion of latching element or plate 3 has two straight line edges 13 and 14 formed therein. These edges 13 and 14 are disposed with respect to each other at an obtuse angle and edge 13 releasably engages trip element 7 while edge 14 releasably engages trip element 11. The plate 3 is movably mounted in the bar 1 by virtue of a guide slot 15 therefor formed in the upper surface of bar 1. The adjusted position of the plate 3 can be fixed by a screw 16 passing through a slot 1'7 formed in plate 3 and into bar 1. The front and rear edges of the plate 3 and slots 15 and 17, exclusive of front edge 14, are disposed parallel to the edge 13. This means that trip element or elongated plate 3 can be moved for adjustment in only one direction which is parallel to the edge 13. Accordingly, when the plate 3 is adjustably moved only the trip point of the trip element 11 is altered while the trip point of the trip element 7 is unchanged.

In Fig. 3 is shown another form of my invention wherein the parts thereof similar in function to the parts of Fig. 2 are given like reference numerals except that they are primed. The front and rear edges of the plate 3 and slots 15' and 17 exclusive of the front edge 14 extend parallel to the front edge 13. The edge 13' latches the releasable signal means trip element 7 and the edge 14' latches the releasable circuit breaker trip element 11. When the screw 16 is loosened and the plate 3' is moved within the slot 15 formed in the bar 1' the direction of movement of plate 3 is parallel to the straight edge 13'. That is, the degree of overlap of the indicating or signal means trip element 7 with respect to the edge 13 is unchanged when the degree of overlap of the circuit interrupter on breaker trip element 11 with respect to the edge 14 is altered. Thus, in this Fig. 3 form of the invention the adjusting means also adjusts the circuit breaker trip point independent of the indicating means trip point.

While there have been shown and described particular embodiments of the invention, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention, and therefore it is intended by the appended claims to cover all such changes and modifications that fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An adjustable latching mechanism comprising a movable latching element having two releasable movable elements engaged therewith for movement one after the other upon movement of said latching element, said latching element having two generally straight nonparallel latching edges which are disposed with respect to each other at an angle and engaged by said releasable elements, and said latching element being mounted for movement in a direction generally parallel to one of said edges.

2. An adjustable latching mechanism comprising a movable common latch element for releasably holding two movable trip elements, one of said trip elements being movable before the other of said trip elements upon movement of said latch element away from said trip elements, said latch element having two nonparallel latching edges which are disposed with respect to each other at an angle and having said trip elements releasably engaged therewith, and said latch element being mounted for movement in a direction generally parallel to the latching edge engaged by the trip element which moves first.

3. An adjustable latching mechanism comprising a movable common latching plate, a peripheral portion of said plate having two straight line edge portions formed therein which are disposed with respect to each other at a generally obtuse angle, a pair of releasable trip elements having portions thereof overlapping said edge portions, one of said trip elements having a lesser degree of overlap with respect to one of said edge portions than the other of said trip elements has with respect to the other of said edge portions whereby when said latching plate is moved generally away from said trip elements said one trip element will be released before said other trip element, and means for adjusting the trip point of said other trip element independent of the trip point of said one trip clement comprising a mounting for said plate whereby it can be moved in a direction generally parallel to said one edge portion.

4. An adjustable latching mechanism comprising a fiat elongated plate mounted for pivotal movement about a generally lengthwise extending axis thereof, one of the sides of said plate having two latching edges therein which are disposed with respect to each other at an obtuse angle, a first releasable trip element having a portion thereof disposed in overlapping latching relationship with respect to one of said edges and another releasable trip element having a portion thereof disposed in overlapping latching relationship with respect to the other of said edges, the degree of said overlapping latching relationship being lesser for said first trip element than for said another trip element whereby when said one side is moved away from said portion said first trip element will be released first, and the trip point of said another trip element being adjustable independent of the trip point of said first trip element by movement of said plate in a direction generally parallel to said one edge.

5. In a circuit breaker having an indicating means actuatable to an indicating condition prior to tripping open of said circuit breaker, means for adjusting the trip point of said circuit breaker independent of the trip point of said indicating means, said adjusting means comprising a movable latch plate having a pair of nonparallel latch edges formed in one side thereof, said pair of latch edges disposed with respect to each other at an obtuse angle and adapted to be overlapped by portions of circuit breaker and indicating means trip elements, and said circuit breaker trip point being adjustable by movement of said plate in a direction generally parallel to the latch edge overlapped by the indicating means trip element portion.

6. In a circuit interrupter having an indicating means actuatable to the indicating position prior to actuation of said circuit interrupter to the tripped open position, means for adjusting the trip point of said circuit interrupter independently of the trip point of said indicating means comprising a latching element having two straight line nonparallel latching edges therein which are disposed with respect to each other at an angle and are adapted to releasably engage a circuit interrupter trip element and an indicating means trip element, and said latch element being movable in a direction generally parallel to the edge having said indicating means trip element engaged therewith.

References Cited in the file of this patent UNITED STATES PATENTS 2,096,608 Combi Oct. 19, 1937 2,169,586 Leonard Aug. 15, 1939 2,487,534 Favre Nov. 8, 1949 

